Cell to surface adherence in Streptococcus mutans apparently involves the synthesis of adherent glucans from sucrose by streptococcal cells and the binding of the cells to these adherence polysaccharides via a specific glucan receptor of the cells surface. The research proposed here will examine the individual biological and biochemical events which the adherence mechanism comprises. Structures of adherent glucans will be studied to determine those glucan structures required for adherence of glucan to smooth surfaces and for optimun binding S. mutans cells. A glucan-binding protein identified in S. mutans extracts will be purified, and characterized. Several carbohydrate receptors have been observed in oral streptococci other than S. mutans. These sugar-specific binding sites may facilitate bacterial adherence to various host tissues, including the oral surfaces, and thus may be major determinants of bacterial pathogenicity. Results of these studies will define the mechanisms of cell to surface adherence and cell to cell adherence which initiate the formation of dental plaque.